Carbon Fibre Repair

DIY rather than professional but I've used 'Q-bond' Q-Bond – Quick Bonding Ultra Strong Adhesive and Filling Powders with the black filling powder to repair stone damage on my CF 'V' piece and hugger.

When it's rubbed down and lacquered it blends in quite well, obviously doesn't give the weave appearance but for small holes it really doesn't show that much, unless on a major component in full view. Might be OK for a belly pan?

 

Wear a mask when playing around with it, particularly when cutting or rubbing down.

Ordinary filler etc won't stick to it well.....it needs to be a resin based (Araldite may work).

 

I would have thought that cosmetic carbon was a throw away item rather than a repairable. Structural carbon as used on the Harrier is a different matter. We did have repairs for large structural parts like wings, but other parts like control surfaces were never designed to be repaired as replacement was more cost effective.

 

I have a feeling that Q-bond is probably the same as plas-tech, a filler/adhesive I used many times on plastic fairings to great effect. Judging by the 'O' ring demonstration in the video, it's probably cyanoacrylate, in which case it will eventually be affected by water. Depending on how big the hole is, you could lay up a small amount of fibreglass matting even but as said, the bonding won't last like the original. I will probably get shot down in flames for this last recommendation, but I remember repairing the keel of a smashed up fibreglass boat some 40 years ago with fibreglass matting and copious amounts of resin. The repair was over 4 feet long and we use the boat for many years afterwards without a leak. I think surface area was the key here, as we overlapped the area really generously.

 

If you are happy to have a go yourself then the company below does some good products which might help.

There are also some videos on Youtube that this company has posted to give you more of an idea.

I use them myself and have found them to be efficient and reliable.

http://www.easycomposites.co.uk/#!/

 

I have tried several 'glues' on carbon fibre.........sometimes it all depends on the overall finish; ie whether it has been lacquered or not.

In both laqured and not (ie relying on the gel-coat finish) Araldite appears to stick if used as a bed between the damaged surface and a patch, but supaglue seems to be easily picked off..........Most plastic glues seem to stick to the lacquer, but not well; however on the gel coat, they won't stick.

If I were the OP, I would get enough cf mat and the resin, then lay a cover over the whole side so that any joins are hidden (say, along the bottom) or even, recover the whole item......skill needed in getting the smooth outer face though.........so it need a pattern / mould made first.

Alternatively given the cost, work and time involved I would probaly say 'sod it' and buy another.

 

another vote here for Easy Composites - I used it to patch a hole in my carbon fibre exhaust. Some useful vids on their website.
They sell a film to put on the visible side to keep it smooth. I had as much success (not perfect, but better than not doing it) with a shirt wrapper from a dry cleaners.

I found it no harder than doing fibreglassing.

 

I repaired a 4" split in my carbon belly pan the other weekend. I put some fibreglass mushy stuff on the back for a bit of strength. On the out side I used aroldite with a bit of black paint mixed in. Let it set, rubbed it down and re lacquered it. Decent enough job to go un noticed unless really looking for it.

 

I've repaired CF belly pans with exhaust burn holes and used different techniques, can you post a photo of the damage @Pavey :Watching:

 

don't be stingy with the overlap as it can only help to strengthen the repair area and no-one is going to see it inside anyway.

 

@Bob T Thin skinned honeycomb panels such as control surfaces and fairings on civil aircraft are certainly repairable - we do it all the time as it is much more cost effective than replacement...have you seen how much Airbus and Boeing charge for these things? Astronomical price! We had a quote for a spoiler the other day (about 5 ft x 1.5 ft) and it was over $100K!
Sorry to digress...

R

 

Steve at C tech composites does great repairs.

C-Tech Composites Ltd UK - Composite Engineering Excellence

 

Have you started to rub I'd down yet? I bet you can get a lot of that out!